Which leaveth her eggs in the earth - That is, she does not build a nest, as most birds do, but deposits her eggs in the sand. The ostrich, Dr. Shaw remarks, lays usually from thirty to fifty eggs. The eggs are very large, some of them being above five inches in diameter, and weighing fifteen pounds - Goldsmith. "We are not to consider," says Dr. Shaw, "this large collection of eggs as if they were all intended for a brood. They are the greatest part of them reserved for food, which the dam breaks, and disposeth of according to the number and cravings of her young ones." The idea which seems to be conveyed in our common version is, that the ostrich deposits her eggs in the sand, and then leaves them, without further care, to be hatched by the heat of the sun. This idea is not, however, necessarily implied in the original, and is contrary to fact. The truth is, that the eggs are deposited with great care, and with so much attention to the manner in which they are placed, that a line drawn from those in the extremities would just touch the tops of the intermediate ones (see Damir, as quoted by Bochart, "Hieroz." P. ii. Lib. ii. c. xvii. p. 253), and that they are hatched, as the eggs of other birds are, in a great measure by the heat imparted by the incubation of the parent bird.
It is true that in the hot climates where these birds live, there is less necessity for constant incubation than in colder latitudes, and that the parent bird is more frequently absent; but she is accustomed regularly to return at night, and carefully broods over her eggs. See Le Valliant, "Travels in the Interior of Africa," ii. 209, 305. It is true also that the parent bird wanders sometimes far from the place where the eggs are deposited, and forgets the place, and in this case if another nest of eggs is seen, she is not concerned whether they are her own or not, for she is not endowed with the power of distinguishing between her own eggs and those of another. This fact seems to have given rise to all the fables stated by the Arabic writers about the stupidity of the ostrich; about her leaving her eggs; and about her disposition to sit on the eggs of others. Bochart has collected many of these opinions from the Arabic writers, among which are the following: Alkazuinius says, "They say that no bird is more foolish than the ostrich, for while it forsakes its own eggs, it sits on the eggs of others; from the proverb, "Every animal loves its own young except the ostrich."
Ottomanus says, "Every animal loves its own progeny except the ostrich. But that pertains only to the male. For although the common proverb imputes folly to the female, yet with her folly she loves her young, and feeds them, and teaches them to fly, the same as other animals." Damir, an Arabic writer, says, "When the ostrich goes forth from her nest, that she may seek food, if she finds the egg of another ostrich, she sits on that, and forgets her own. And when driven away by hunters, she never returns; whence, it is that she is described as foolish, and that the proverb in regard to her has originated.
And warmeth them in dust - The idea which was evidently in the mind of the translators in this passage was, that the ostrich left her eggs in the dust to be hatched by the heat of the sun. This is not correct, and is not necessarily implied in the Hebrew, though undoubtedly the heat of the sand is made to contribute to the process of hatching the egg, and allows the parent bird to be absent longer from her nest than birds in colder climates. This seems to be all that is implied in the passage.

Which leaveth her eggs in the earth - This want of parental affection in the ostrich is almost universally acknowledged. Mr. Jackson, in his Account of Morocco, observes: "The ostrich, having laid her eggs, goes away, forgetting or forsaking them: and if some other ostrich discover them, she hatches them as if they were her own, forgetting probably whether they are or are not; so deficient is the recollection of this bird." This illustrates Job 39:15 : "And forgetteth that the foot may crush them, or that the wild beast may break them." The poet seems well acquainted with every part of the subject on which he writes; and facts incontestable confirm all he says. For farther illustration, see the account from Dr. Shaw at the end of the chapter, Job 39:30 (note).

Which leaveth her eggs in the earth, and (h) warmeth them in dust,
(h) They write that the ostrich covers her eggs in the sand, and because the country is hot and the sun still keeps them warm, they are hatched.

Which leaveth her eggs in the earth,.... Lays them and leaves them there. Aelianus, agreeably to this, says (w), that it builds a low nest in the ground, making a hollow in the sand with its feet; though he seems to be mistaken as to the number of its eggs, which he makes to be more than eighty; more truly Leo Africanus (x), who reckons them ten or twelve; which, he says, it lays in the sand, and each of them are of the size of a cannon ball, and weigh fifteen pounds, more or less. Hence, with the Arabs, it is called
"the mother of eggs,''
because of the large eggs it lays; and with them it is a proverb,
"meaner, or of a lesser account, than the eggs of an ostrich,''
because its eggs are neglected by it (y);
and warmeth them in the dust; not that she leaves them to be warmed by the hot sand, or by the heat of the sun upon them, by which they are hatched, as has been commonly said, for thereby they would rather be corrupted and become rotten; but she herself warms them and hatches them, by sitting upon them in the dust and sand: and for this the above historian is express, who says (z), the female lighting on these eggs, whether her own or another's, sits on them and heats them. Concerning the ostrich hatching its eggs, Vansleb (a), from an Arabic manuscript, relates what is incredible, that they are hatched by the male and female with their eye only; that one or other of them keep continually looking at them until they are all hatched; and this I observe is asserted also by another writer (b).
(w) De Animal. l. 14. c. 17. (x) Ut supra. (Descriptio Africaae, l. 9. p. 766.) (y) Hottinger. Smegm. Orient. l. 1. c. 7. p. 128. (z) Descript. Africae, ut supra. (l. 9. p. 766.) Vid. Aelian. l. 4. c. 37. (a) Relation of a Voyage to Egypt, p. 64. (b) Coelius, l. 10. c. 5. apud Sanctium in loc.

Yet (unlike the stork) she "leaveth," &c. Hence called by the Arabs "the impious bird." However, the fact is, she lays her eggs with great care and hatches them, as other birds do; but in hot countries the eggs do not need so constant incubation; she therefore often leaves them and sometimes forgets the place on her return. Moreover, the outer eggs, intended for food, she feeds to her young; these eggs, lying separate in the sand, exposed to the sun, gave rise to the idea of her altogether leaving them. God describes her as she seems to man; implying, though she may seem foolishly to neglect her young, yet really she is guided by a sure instinct from God, as much as animals of instincts widely different.